In the field semiconductor technology, due to its advantages like high mobility, simple process, low cost, uniformity over a large area, a metal oxide TFT (thin film transistor) has gradually replaced the conventional amorphous silicon (a-Si) TFT and low-temperature polycrystalline silicon (LTPS) TFT, and has become a key device for driving an OLED display panel.
Currently, the metal oxide TFT is also of great interest in AMOLED (active matrix organic light emitting diode) of the next generation technology innovation, which is also called as an OLED display panel. WOLED+CF (i.e., RGBW color filters are used in combination with a white OLED light emitting material to realize color display) represents a development trend of the AMOLED. It has attracted much attention due to advantages like a high utilization rate of an organic EL material, a low requirement for the evaporation mask, and a large aperture ratio when a top-gate metal oxide TFT is adopted.